NRG Tablets provide a strong visual for east detection------Save money and save water by detecting silent leaks with our package of 2 dye tablets. Simply drop tablet in tank and know in a few moments if a repair needs to be made. Tablets are non-toxic and FD&C safe. Instructions in English and Spanish. One of the most effective water conservation measures you can take. Dye tablet 10 pack. NRG Authentic tablets have a strong blue visual!